Thermal circuit closer



Patented Sept. 4, 1928.

N l T D Inter-n enny'son, or (initiation, wiisr tr maran, I

THERMAL o'rrtcii'r'r cream.

Application filed-March 9, 192a Se'rial no. 9 ,519. Y

This invention relates to circuit closers for fire alarm systems such as d-isolosedin my copending application, Serial No. 97,691, filed March 26, 1926, andhas for its object to provide such a device which has destructible means normally sustaining a contact in a position to retain the alarm circuit open, and which,when the means supporting the contact is destroyed 'by firaheat or in any other Way will close the circuit and cause a bell or other signal to be operated at any suitable and coI'iv'enieht point.

A further object of the invention resides in the provision of such a device which may. be made at low cost, and which comprises very few parts; which may be readily installed in houses or factories in an inconspicuous manner to automatically sound an alarm, and which is so constructed that it will not readily get out of order.

Other objects and advantages of the invention will be apparent from the following description when taken in connection with the accompanying drawing; in which Figure 1 is a greatly enlarged vertical section through the box, contacts and fusible plug; the spring being shown in side elevation, and

Figure 2 is a vertical section on line 2-2 of Figure 1.

Referring to the drawing in greater detail the numeral 1 designates acasing made of any suitable insulating material such as hard rubber or the like and provided with a cover 2 also formed of insulating material.

As hereinbefore indicated it is an of the present invention to provlde a heatresponsive switch of simple and inexpensive.

construction, and to this end the casing 1 is provided with two parallel channels 3 and a and atransverse passageway 5 all stamped in the insulating material'at the time the casing is formed.

, Mounted for sliding movement within the channel 3 is a movable contact element 6 carrying the laterally extending contact 7. This contact 7 and its support 6 may be integrally formed of somerconducting material as shown in Figure 1, or the two parts may be separately formed and attached together. In the latter case the element 6 of course might be made of non-conducting material.

Fixedly mounted iii-opposite ends ofthe channel are the contact pieces 8 and 9 to object which are connected "the lin'e'wires 1'0 and 11 resp ec tively leading to the-source'of 'p Owen, aiming-etc. Also mounted in the channel 41's acompr'ession spring 12 whichisin en'- ga'gement with the fixed contact 8 and the upper surface or the movable contact 7.. The

construction'would of course force the 'm'ovable'contact 7 into engagement with the contact :9 were it not forith'e factthatthecontact 7 is normally held in its upper in 'a manner now to be described; .It will 'be noted that the channel "3 extends entirely through one end of the casing 1 as indicated by the numeral 13 and this portion of the channel is formed with a recess 14; adapted to form a seat for the plug 15 formed of any suitable fusible material. This plug of course, is placed in position after the element 6 and contact 7 are forced upwardly as shown in Figure 1 thereby holding the spring 1 compressed and in inoperative position.

In practice, the device which is many times smaller than the illustrated size may be placed on the molding in a room or supported on the wires themselves. Should the temperature of the room, store, or the like become excessively high due to a fire the plug will be destroyed and the spring 4 will force the movable contact 7 into engagement with the fixed contact 9 thereby closing the circuit, the current passing through line wire 10 contact 8 spring 12, contacts 7 and 9, line wire 11 to the alarms, etc.

From the foregoing description taken in connection with the accompanying drawing it will be apparent that I have devised an extremely cheap and simple heat-controlled circuit closer, and yet one which is durable and reliable in operation. It should be noted however, that the accompanying drawing is intended to be merely illustrative of one form of the invention and should not be considered in any limiting sense except in so far as defined by the accompanying claims.

position What I claim as new and desire to secure by Letters Patent is:

1. A thermal circuit closer comprising a casing having a pair of parallel channels therein, and a communicating passageway forming a support for said movable contact, electric conducting means in contact with one of said fixed contacts and said movable contact for biasing the latter toward the other fixed contact, and fusible means for normally holding said biasing means inoperative.

2. A thermal circuit closer comprising a casing of insulation material having a pair of parallel channels therein and a transverse passageway communicating therewith, a pair of fixed electric contact members positioned in opposed ends of one of said parallel alignment with said first-named contacts. a

spring engaging one of said fixed contacts and said movable contact so as to bias the latter toward the other fixed contact, and

fusible means for normally holding said spring inoperative.

3. A thermal circuit closer comprising a casing having a pair of parallel channels therein, a communicating passage between said channels, and an opening through one end of the casing and communicating with one of said channels, fixed contacts in one of said channels, a movable contact in align ment with said fixed contacts, a rod slidably mounted in the other of said channels and forming a circuit for sald movable contact,

electric conducting means in contact with one of said fixed contacts and said movable LLOYD GRAYSON. 

